Of the older clocks used in the Specola, this one by Daniel Quare and its twin - presently held in the University Library - are the only ones to survive.
To safeguard the case, often made of valuable wood, it was not uncommon for a second case of rougher design to be built to house the mechanism so as to avoid wear and tear to the original. Indeed, referring to a French clock by Isaac Thuret, purchased from Cassini, Manfredi told Marsili that immediately after its delivery he had placed it in an ordinary wooden tower (see Part I, par. 12, note 100). It was in this way that the clocks most valued by the astronomers disappeared without trace while these two, judged unsatisfactory from the start, survived.
The quaker Daniel Quare had been watch-maker to William II and had specialized in the production of transportable thermometers and barometers. For the construction of these latter he had obtained a patent in 1695 and worked it with the then famous watch-maker Thomas Tompion.
Manfrediís hand-written note on Instrumenta quibus observationes peraguntur in hoc observatorio (scilicet Marsili Observatory) records a "Horologium Londiniense Quarei dictum A" and a "Horologium Londiniense aliud Quarei dictum B".
A letter from Manfredi to Marsili, dated 10 January 1702 (Univ.Bo. Library, Mss.Marsiliani 80A), had in fact mentioned the arrival of two English clocks which had been entrusted to "watch-maker Santino" (probably Sante Menini [file 13]) to be cleaned.
A letter written shortly after, however, on 7 February 1702 (Univ.Bo.Library, Mss. Marsiliani 80A) declared that, however accurate they might be, the clocks were not suitable for astronomical observations, since they were not regular enough in their operation. An entry in the Records of the Marsili Observatory confirms that they were never used for observations. In fact, already in the 1712 Instrumentum Donationis, the clocks in question are no longer listed among the instruments of the Specola.
One was tracked down to the Institute of Physics at the University and, after being restored in 1979 by G. Morigi (Bologna), can now be seen in the Meridian Room of the Specola. The other is in the University Library.
The hours on the dial are in Roman numbers, the minutes in Arabic; within the hour dial a smaller dial tells the seconds and a square window displays the days of the month.
E. Baiada, A. Braccesi (1983) pp. 82-83 e 92, fig. 2.
M. Daumas (1953) p. 96.
Gli orologi antichi (1988) pp. 68-69.